Common Eye Disorders > Macular Degeneration
What is age-related macular degeneration?
Age-related macular degeneration (ARMD) is a very common cause of reduced vision. As the name suggests, it is a condition that tends to become more common as people get older.
Although this condition may cause significant reduction in vision it never leads to complete blindness as it affects only the central part of the vision and the side, or peripheral, vision is always left intact.
The retina, which is situated at the back of the eye, transmits the images that we see to the brain. The retina has two main parts – the macula and the peripheral retina.
The macula is the part of the retina that is responsible for seeing fine detail, such as reading, seeing facial features and interpreting different colours. It is this part of the retina that is affected by age-related macular degeneration.
How does ARMD develop?
This is an ageing change and occurs because of ‘wear and tear’ in the macular region. It is thought that waste materials from this very active part of the eye build up as the mechanisms for removing them become less able. This causes damage to the cells over a period of time.
Who is a risk of age-related retinal degeneration?
The condition tends to affect people who are over 60 years of age. Some younger people may be more susceptible, including people who are very short-sighted. Woman tend to be affected more commonly than men, but that is probably because they live longer. There is a hereditary tendency, but this has not yet been fully researched.
What are the different types of macular degeneration?
There are two major types of ARMD. These are described as dry or wet.
This is the more common form of ARMD and affects almost 80 percent of those with the condition. The onset of this tends to be slow. Both eyes are usually affected symmetrically.
Wet macular degeneration is less common but has a more severe and rapid effect on the central area of vision. In this condition, blood vessels at the back of the eye grow in an abnormal fashion into the macular area. These blood vessels may leak or bleed causing a rapid and significant reduction in central vision. This tends to affect one eye at a time but there is a risk of the same thing occurring in the other eye over the following months.
What are the symptoms of age-related macular degeneration?
Dry ARMD causes a gradual reduction in central vision. This tends to affect the ability to read and to see fine detail more than distance vision.
The first symptoms of wet ARMD may be distortion of vision (known as metamorphopsia). This often has the effect of making straight lines appear curved or tilted. The vision deteriorates and eventually the central vision may be completely lost leaving a dark central area of poor vision (known as a central scotoma).
What macular degeneration treatments are available?
There is research being carried out in this area but the macular degeneration treatments are far from universally successful.
The vision tends to deteriorate gradually and the loss of vision is not always severe. macular degeneration treatment involves wearing the best spectacle prescription and using bright lights. The use of large print books and magnifying glasses or low visual aids is often necessary.
In order to determine whether a patient would be suitable for macular degeneration treatment, further evaluation and imaging of the retina needs to be carried out. Imaging of the retina involves a fluorescein angiogram and a scan of the back of the eye (retina) with an OCT (optical coherence tomography) machine.
The fluorescein angiogram procedure involves a dye being injected into a vein of the arm and then a series of photographs are taken of the back of the eye. An OCT scan is used to look for macular degeneration under the retina and this scan usually takes only a few minutes to perform.
If wet ARMD is confirmed, treatment is implemented urgently.
There are currently two wet macular degeneration treatment procedures, firstly with injection of medication into the back of the eye and secondly with laser eye treatment.
Depending on the level of vision and retinal imaging, some wet ARMD may be suitable for injection with a drug called Avastin or Lucentis into the back of the eye. This medication works by preventing the formation of abnormal new blood vessels and dries up fluid that has leaked into the retina. While these injections are currently accepted as the most effective treatment available in preventing further sight loss, it is not successful in all cases.
Injections are given every six weeks for three injections and subsequent injections may be repeated during the follow-ups if evidence of recurrent disease is diagnosed.
Additionally, laser eye treatment photo-dynamic therapy (PDT) which uses a light-sensitive dye called verteporfin (Visudyne) in combination with laser treatment is also sometimes used to treat certain kinds of wet ARMD. The dye is first given by injection and then the laser is used to activate the dye and close off the new blood vessels that cause the damage.
Further evaluation of macular degeneration treatment in the form of clinical trials is underway and hopefully will guide clinicians in making decisions in treatment of this visually debilitating disease.
What can be done to avoid getting ARMD?
There has been much discussion about the role of high dose vitamins in preventing this condition, and in certain situations they can reduce the chance of getting severe ARMD. A person who has wet ARMD in one eye should have the vision in their other eye regularly assessed so that early signs of distortion are picked up rapidly. This can be done by looking at picture frames or by using an Amsler Chart, which their ophthalmologist should give to them. Patients on macular degeneration treatment should be assessed every six months to a year, depending on severity.
If you are researching macular degeneration treatment, the cost thereof in South Africa or searching for an eye specialist in Cape Town, please contact one of our practices where our qualified assistants are able to provide professional and friendly guidance.